Patient harm, patient safety and their governance have been ongoing concerns for policymakers, care providers and the public. In response to high rates of adverse events/medical errors, the World Health Organisation (WHO) advocated the use of surgical safety checklists (SSC) to improve safety in surgical care. Canadian health authorities subsequently made SSC use a mandatory organisational practice, with public reporting of safety indicators for compliance tied to pre-existing legislation and to reimbursements for surgical procedures. Perceived as the antidote for socio-technical issues in operating rooms (ORs), much of the SSC-related research has focused on assessing clinical and economic effectiveness, worker perceptions, attitudes and barriers to implementation. Suboptimal outcomes are attributed to implementations that ignored contexts. Using ethnographic data from a study of SSC at an urban teaching hospital (C&C), a critical lens and the concepts of ritual and ceremony, we examine how it is used, and theorise the nature and implications of that use. Two rituals, one improvised and one scripted, comprised C&C’s SSC ceremony. Improvised performances produced dislocations that were ameliorated by scripted verification practices. This ceremony produced causally opaque links to patient safety goals and reproduced OR/medical culture. We discuss the theoretical contributions of the study and the implications for patient safety.